Saturday, 10 April 2010

Five a day does not stop cancer

Eating five servings of fruit and vegetables a day does little to reduce a person’s risk of cancer, according to a new study.

The findings, published recently, run counter to long-standing advice that regular helpings of fruit and veg will lower cancer risk.

The World Health Organisation in 1990 recommended eating five servings a day to reduce cancers, and this is also heavily promoted in the US, UK and Australia.

But studies since then had failed to confirm there was any specific health benefit in adhering to the “five a day” message, the authors point out in their research, which appears this morning in the Journal of the National Cancer Institute published by Oxford University Press.

The study included 142,605 men and 335,873 women. These were recruits assembled between 1992 and 2000 for the “Epic” study, European Prospective Investigation into Cancer and Nutrition.

It included participants from 23 centres in Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden and the UK. Details of their eating habits were recorded.

Over the eight years to 2000 more than 30,000 participants eventually developed cancer. On analysis of the numbers, the authors found that there was only a very small association between high intake of fruit and veg and a reduced cancer risk.

They also recorded a “modest” benefit for those keen on vegetables, but the gain was only seen in women, not men.

When they looked at heavy drinkers, those who ate plenty of fruit and veg also saw a small benefit, but the reduction in cancer risk was only seen in tumours related to smoking and alcohol.

The authors, led by Dr Paolo Boffetta of the Mount Sinai school of Medicine in New York and colleagues, warn against any assumption that a specific diet could lead to cancer-risk reduction, this despite the fact that the prevailing wisdom holds five a day can deliver benefits.

The authors do theorise however that high fruit and veg intake may reflect a tendency to other helpful lifestyle choices.

“In this population, a higher intake of fruits and vegetables was also associated with other lifestyle variables, such as lower intake of alcohol, never smoking, short duration of tobacco smoking and higher level of physical activity, which may have contributed to a lower cancer risk,” they say.

My own take on this is that consuming as much food as possible that does not have a residue of chemicals unneeded by the human body has to be good. Anything else is risking adverse effects.